Organic arsenic compound-bearing lubricants



Patented Sept. 29, 1942 ORGANIC ARSENIC COMPOUND-BEARING LUBRICANTS Bert H. Lincoln and Gordon D. Byrkit, Ponca City, Okla., assignors to Continental Oil Company, Ponca City, Okla., a corporation of Delaware No Drawing. Application March 14, 1940. Serial No. 323,960

9 Claims.

This invention relates to improvements in lubricants. More specifically, this invention relates. to improved materials which, when added to lubricants, greatly increase their resistance to oxidation and formation of corrosive products during use and often improves other characteristics as well. This application is a continuation-inpart of our copending application, Serial No. 231,- 362, filed September 23, 1938.

Present-day mechanical devices require lubricating oils of high film strength, of high oiliness characteristics, and of low tendency to oxidize during use. It has been found that the presentday hydrocarbon lubricants of the very highest quality are deficient in these very important characteristics. 1 These three properties are of vital importance under conditions of thin film lubrication where the lubricant has been squeezed from between the friction surfaces because of high pressure, slow speeds, and other causes. It is readily seen that the viscosity or the body of the lubricant plays no part in this type of lubrication and that the remaining film of oil must have a very high film strength and be of high oiliness value to prevent rupture of the film of the lubricant, which would cause seizure. The oil film must tend to keep the coefficient of friction as low as possible. The oil must resist oxidation when these thin films are heated in the presence of oxygen as they are in use.

Mechanical devices are being designed for higher pressure operation and the film strength of the best quality straight hydrocarbon lubricant has been found to be too low. It will be obvious that an invention which provides a means of improving the filmstrength of these lubricants is of great importance to the art of lubricant manufacture and to the designer and fabricator of mechanical devices.

Substantially all machines operate in part or attimes totally under conditions of boundary or thin film lubrication, under which conditions the oiliness or unctuosity of the lubricant is the first and primary requisite of efficient operation. Those skilled in the art of lubricant manufacture or machine manufacture will readily ap- Furthermore, sludge and acid are a hydrocarbon lubricants are used. With dry friction, the wear on friction surface is extreme; and during cold weather when the lubricant is sluggish or during periods when the lubricating system is not functioning properly for one reason or another, rubbing surfaces may not only suffer considerablewear but may be damaged to the point where they must be replaced. The product of our invention has a very important property of reacting with the metal surfaces, penetrating or adsorbing on the metal surfaces, and leaving a film of lubricant with'high oiliness character, which remains on the metal surface irrespective of the length of time the machine has been idle.

This high oiliness film gives very even and smooth operation, which may be easily discerned by the experienced operator or lubricating engineer.

When the hydrocarbon lubricants are diluted with unburned fuel or with other light hydrocarbons, the small degree of oiliness of the original hydrocarbon lubricant is greatly decreased. We have found that the addition of the products of our invention to hydrocarbon lubricants more than compensates for the loss in oiliness and loadcarrying ability from dilution.

It is well known that, in order to obtain lubricants which are preeminently satisfactory from the standpoint of oxidation in use, it is necessary to refine the oil thoroughly and then to add an inhibitor of oxidation. The thorough refining may consist of more and heavier acid treatments or solvent treating so as to remove a considerable part of the oil and leave only the most stable portion. Such drastic refining is necessary in order to obtain stability with respect to sludge formation, but the oil is then subject to easy oxidation to form soluble acids and other corro-- sive materials. This can be prevented by the addition to the refined oil of small amounts of materials which either prevent the formation of these corrosive products or by the same action render them inert. Furthermore, such well-refined oils are susceptible to the formation during use of lacquerlike materials which tend to stick rings. This results in a blow-by and hence loss of power, failure of lubrication, scratching, scoring, overheating, and eventually replacement of parts. It is practically impossible to refine a lubricant in such a manner as to avoid all three of these difliculties, namely, sludge, solubl corrosive products, and lacquer. It is considerably more advantageous to add the materials of our invention and avoid these .difficulties by this method.

Many of these additive materials are effective when added to poorly refined or even wholly unrefined lubricants. The addends may thus be substituted in whole or in part for the usual refining processes.

In the prior art of applying these principles to the manufacture of lubricants, manydiverse types of materials have been suggested to be added to obtain improvement in various characteristics. It has'been found that the addition of various organic esters of the oxygen and sulfur acids of phosphorus frequently improves film strength, oxidation resistance, non-corrosiveness. and other characteristics. Nitrogen compounds have been found to inhibit oxidation of oils. Our materials combine both of these properties.

One object of our invention is to provide improved inhibitors of oxidation and corrosion for addition to lubricants.

Another object of our invention is to provide film strength improving addition agents suitable for use in lubricants and especially in crankcase lubricants. 1

Other and further objects of our invention will appear in the course of the following description.

Ingeneral, our invention'consists of the addition of certain organic arsenic compounds containing at least one arsenic-nitrogen bond to hydrocarbon' fuels and lubricants. These materials combine the advantages of phosphorus compounds of nitrogen compounds and are frequently even more effective in preventing the development of corrosive materials in the oil during use than their nitrogen and phosphorus analogues. Some of these materials which are suitable for use in accordance with our invention are shown in the following outline. All and each of these are to be considered as examples of our invention when blended in an oil of lubricating viscosity.

dichlo- C. Arsen-aryl amino diethers, RNHAS(OR' ')2 (R is aromatic ;-.R' is aliphatic or aromatic) 1. Arsen-anilino dimethyl ether,

CsHNHAS (OCHs) 2 2. Arsen-o-chloroanilino dicyclohexyl ether C1C6H4NHAS(OC5H11)2 '3. Arsen-toluidino dicresyl ether CH3C'6H4NHAS (OCsH4CI-I3) 2 4. Arsen-anilino dibenzyl ether CsH5NHAS (OCHzCcI-Is) 2 Any of these compounds or other members of the classes represented or their derivatives within the limitations set forth above may be used within the scope of our invention.

It is to be understood that in practicing ou invention, oil-soluble arsenic-nitrogen compounds of the type described are to be selected. Some of the examples described have only limited solubility in hydrocarbon oils. It is to be remembered, however, that, because of their great efficiency, extremely small amounts are often effec-v tive. Thus we may useas little as 0.001 per cent of some of these compounds, and it will be seen rendered more soluble by the introduction of al- 'other purposes we prefer naphthenic or mixed base lubricants. Another method of obtaining a satisfactory mixture of addition agent with the hydrocarbon oil is the use of a mutual solvent to bring the addend into solution. Alternatively,

peptizing agents may be added to maintain the.

organo-arsenic compound in permanent suspension.

Many of the more diificult soluble materials are kyl groups, particularly those containing four or more carbon atoms. The isoamyl, octyl, lauryl. and octadecyl radicals and radicals from paraffin wax greatly. increase the solubility of organic compounds in oil. One or more of such groups may be introduced as required into the previously described compounds or their derivatives. example, arsen-anilino dimethyl ether is not very soluble in'hydrocarbon lubricating oils but arsenp-tert.-butylanilino' dilauryl ether is much more soluble.

The selection of a particular compound or compounds to beused as an addition agent t the hydrocarbon oil is to be made considering .the use to which the blend is put. Thus, if water is likely to be present during use, an arsenic compound or combination of compounds is selected which is not affected by water. In general, we prefer to use compounds having boiling points over 250 F. It .is sometimes advantageous tocombine more than one of these compounds in a blend to obtain particular properties. We accomplish this by mixing two or more of these compounds together and .blending the mixture with the hydrocarbon oil or by blending'one in the hydrocarbon oil, blending the second into this mixture, and so on until'the composition is complete.

The various arsenic-nitrogen compounds usually improve both the filmstrength and oxidation characteristics of the hydrocarbon oil. For example, the sludging tendencies may be decreased by as little as 0.001 per cent of our arsenic nitrogen compounds. of lubricants are very important, and these are markedly improved by our compounds. The ability to reduce friction is another feature contributed to lubricants by our arsenic-nitrogen compounds.

It may be desirable to include in one and the same blend based on a hydrocarbon oil, in addition to the addends here described, other addends for specific purposes. Thus, we may add a, pour point depressor such as a naphthalen'echlor wax condensation productand a viscosity index improver such as certain resins or polymerized hydrocarbons in addition to our organ o-ars enic compounds. Furthermore, various metallic compounds may beadded to the blend without interfering with the action of our ingredients. In-

deed, in some cases it is advantageous to combine with our organic arsenic-nitrogen compounds in a hydrocarbon oil blend such materials as calcium 'dichlorostearate, chromium oleate, tin octadecyl phthalate, aluminum stearate, and other metallic soaps.

For

The oxidation characteristics- Our addends are admirably adapted for use in lubricating oils of all types including those designed for use in automotive crankcases, Diesel oils, and any other oils of lubricatingviscosity such as castor oil, cottonseed oil, lard oil, sperm oil, shale oil. Furthermore, our addends are advantageously blended in gasoline and other pe troleum fuels either directly or after being blended first in a lubricating oil and then added to the fuel. Soap-thickened mineral oils of all types ranging from those showing only a slight increase in the final blended fuel may vary from 0.0001 to 1.0 per cent or slightly more.

in viscosity over that of the mineral oil alone to the semisolid and solid greases containing fifty per cent or more of soap are amenable to treatment according to our invention. In making these greases, the usual soaps such as sodium stearate, aluminum stearate, calcium soaps of beta fat and the like may be used. Various other thickening ingredients or materials for other purposes may be added. These include yarn, hair graphite, glycerol, water, lamp black, mica, zinc dust, litharge, and the like. I

The following examples of blends of our addition agents are given as illustrations and not as limitations:

. Example 4 In making a grease, containing our addends,'we

may use:

Per cent Oleic acid--- 8.1 Lime 1.2 Water- 0.3 Dichlorostearic acid 1.1 Bright sto 13.1 Distillate (440 seconds 100 F.) .....r 76.0 Arsenanilino dichloride 0.2

\ Example 5 In making a lubricating gasoline, we blend 0.5 per cent of the product of Example 1 with gasoline. The product has the composition Per cent Gasoline 99.5 Oil 0.495 Arsenanilino dichloride 0.005

It is to be understood, however, that the hydrocarbon oil in the treated fuels may be of a viscosity from about seconds to 100 F. S. S. U. to 350 seconds or more; and the'amount of oil blended with the arsenic-nitrogen compound to It will be understood that certain features and sub-combinations may be employed without reference to other species or combinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is therefore to be understood that our invention is not to be limited to the details described.

Having thus described our invention, we claim:

1. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion of an arsenarylaminodihalide.

2. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion of an arsen-d'iarylamino halide.

3. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion of an arsenarylamino diether.

4'. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion of arsenanilinodichloride.

5. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion of arsen-dianilino-chloride.

6. Lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion of arsen-anilino-dimethyl ether.

7. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion of an arsenical derivative of an aromatic amine having the formula (RNH)nASX3-n in which R is an aromatic radical, 11. is at least one but not more than two, and X is a radical selected from the group consisting of halogens and CR radicals in which R is an organic radical, said arsenical derivative being further characterized by a direct arsenic to nitrogen bond and by having no direct arsenic to carbon linkage.

8. A lubricant comprising in combination an oil of lubricating viscosity and from 0.001 to 5 per cent of an arsenical derivative of an aromatic amine having the formula (RNHnAsXa-n in which R is an aromatic radical, n is at least one but not more than two, and X is a radical selected r from the group consisting of halogens and OR radicals in which R is an organic radical. said arsenical derivative being further charactcrizcd by a direct arsenic to nitrogen bond and by having ing of the halogens, said arsenical derivative beform the fuel addend may vary between 0 per ing further characterized by a direct arsenic to nitrogen bond.

BERT H. LINCOLN. GORDON D. BYRKIT. 

